If you are really sharp-eyed you may pick up the strong purposeful flight of a peregrine, or glimpse a merlin dashing by.
The sharp eyed among you might have noticed a gaping flaw in this 1812 engraving by J. Greig.
Some very sharp-eyed lookouts spotted the floating mines before any of our flotilla made contact.
We always welcome comments from sharp-eyed viewers who notice our errors and take the time and trouble to send us corrections.
Sharp-eyed readers will have noted the inclusion of " valid " in that list.